A woman who lived in a squalid, vermin-infested home where the bodies of three infants were found was charged Friday with covering up the deaths, while neighbors said they wish they had acted themselves to call attention to the house with the foul smell and the shades that were always drawn.

Erika Murray, 31, was arraigned on charges including fetal death concealment, witness intimidation and permitting substantial injury to a child. But basic facts remain a mystery or aren't being explained by authorities.

Among them: why it took authorities so long to search the home even after removing four other children from it last month; whether the babies were newborns or fetuses; whether the woman was the mother of all the children; the nature of a 2007 report of abuse or neglect at the house that was not deemed a problem; and the identity of a man who also lived there.

A search by crews in hazmat suits for any more remains continued at the house even as not-guilty pleas were entered for Murray in nearby Uxbridge. A court-appointed defender suggested she was mentally ill.

"You want answers in circumstances like this. ... Mental illness doesn't always provide those kinds of answers," said Keith Halpern, Murray's attorney, after the arraignment. He did not elaborate on her condition.

In Blackstone, a town of less than 10,000 near the Rhode Island border about 50 miles southwest of Boston, residents fretted that such horrors had gone unnoticed.

"I think everyone in town is feeling a little of that today," said Sarah Martin, 29, who often walked by the home with her own 2-year-old daughter but did not know the family. "When something so tragic and heart-wrenching happens, you look back and say, 'Maybe there were clues I could have picked up on.'"

Neighbors said the shades were always drawn; some had noticed a foul smell. A prosecutor said that soiled diapers were piled up 2 feet high and that the remains of several animals had also been found.

The children first came to the attention of police two weeks ago when a 10-year-old boy who lived in the house went to a neighbor and asked, "How do you get a baby to stop crying?" said Tim Connolly, a spokesman for Worcester District Attorney Joseph Early Jr.

The neighbor went with the boy and found the crying baby covered in feces, but no adults around.

Police were called and notified the state Department of Children and Families, which removed the four children — in addition to the 10-year-old, children ages 13, 3 and 6 months — from the home. Murray was then charged with two counts of reckless endangerment, and the house was condemned.

Based on interviews with the two older children, police got a search warrant and went back to the house. That's when they found the remains of three babies, one in a closet on Wednesday and two others on Thursday. A medical examiner is determining whether they were newborns or fetuses.

There was also a man living in the house, and Connolly said he has not been charged with anything.

It's unclear whether anyone fell down on the job. The state Department of Children and Families, already under scrutiny, said Friday that it had received a report of abuse or neglect in 2007, but that it was unsupported and no case was ever opened with the family. The agency did not release details on the nature of the report.

The agency said it responded immediately to the neglect report from Blackstone police and removed the children from the home about one hour later. The lag time between the removal of the older children and the search that led to the discovery of the remains hasn't been explained.

The agency took heat over the case of a 5-year-old boy whose disappearance last year went unnoticed for months even though the boy's family had been monitored by the agency for years. Three employees were fired and a fourth disciplined after an investigation revealed missed social worker visits and other failed opportunities to engage with the family.

A girl who is friends with the 13-year-old who was removed from the home described the girl's mother as determined to keep visitors from entering.

"Like, if it was raining, she'd let the dogs in, but not us," said Taylor Pryor, 13. "Or, if it was, like, snowing or cold or something, she'd only let the animals in and we would have to stay outside, so my mom always told me to go home."

She said she never suspected anything sinister behind the efforts to keep visitors out.

"I just since it was messy. . I thought it was just like a lazy house and they didn't want anyone seeing their mess, but, I guess, it was more than that."

One neighbor said she never heard any major complaints, but noted that her grandchildren once complained the house smelled bad. Another neighbor said she regretted not calling animal control after seeing a dog tied there on a short rope.

A mail carrier, Pam Webster, said that the house appeared dirty and that the children often ate breakfast on the porch.

Barbarajean Calnan, who lived two doors down from Murray's mother, Sharon Murray, in Northbridge, said she knew Erika Murray growing up and was at a loss for words. Erika Murray often came to visit her mother with the two older children, Calnan said, but she never saw any other children.